Heavy metals content in alfalfa cultivated on vertisols along the highway e75 from Belgrade to Leskovac (Serbia)

Abstract

In order to assess the health and safety of animal feed, in ten samples of soil and plant material, collected along the E75 highway from Belgrade to Leskovac, it was examined the content of heavy metals: Cr, Cu, Ni, Pb, Co, As, and their accumulation in alfalfa (Medicago sativa L.) grown on vertisols. Samples of soil and aerial part of the plant material were collected from the both sides of lanes at locations where the studied plant species was cultivated, at 10, 30, 50 and 400 m perpendicular to the direction of the highway. Soil and plant analyses of the metals content were done according to ICP methodology. Analysis of the soil samples showed the following: the content of total forms of Cr and Ni was above the maximum permissible concentration (MPC) in 50% of samples tested; the content of Pb was above the MPC in 30% of samples tested; in the other soil samples the values of the examined parameters were within permissible limits. In five of the ten tested plant samples Cr content was above the toxic concentrations, and in one sample it was above the maximum tolerance levels for animal feed. In one sample of alfalfa it was determined the contents of As and Pb above the toxic levels. In addition, the concentrations of Co and Pb above the normal levels were registered in one sample of plant material, but they were below the maximum tolerance levels for animal feed. The obtained results suggest a caution in the use of alfalfa, grown near the highway route, for animal feed, because of the potential entry of heavy metals into the food chain. The study also revealed that increased concentrations of analyzed elements occurred at all distances from the route lanes.